The long-term monitoring of trees on a permanently marked forest plot gives important information on the structure and composition of a forest, the condition, growth rates and longevity of the species of trees composing that forest, changes in species composition or population size that occur over time and the impacts of environmental change on mature trees and forest ecosystems. Such long-term monitoring is also essential for reliable future assessment and management decisions affecting forest vegetation. Field measurements are recorded once every 5 years during the summer at 10 plots (20 X 20 m2).